Child development is absolutely fascinating. We had a child a week after my cousin and his wife had one. They live quite a way away from us, so we get together on long weekends and holidays in the summer, that sort of thing.
I have an academic background/career, my wife is a teacher. We live in a very rural area. They live in a very, very, urban area. He is a professional maitre d' in a fancy restaurant, and she is, as of recent, a CPA (was previously a chef of some kind).
The children in question are slightly over 2.
Their child is super confident around people. He is very outgoing, he is super friendly and doesn't hesitate to go to you to be picked up if he needs something. He is great on stairs, and is incredibly confident in his jumping off of things. He doesn't really talk. He is incredibly scared of bugs, birds, and any animal larger than a Labrador retriever.
My kid is shy around people. He will go to you, only if we say it's alright first. He sucks out loud on stairs, and jumps off of low objects. He talks in complete sentences and uses new words constantly. He loves picking up bugs and spiders, and is fascinated by all animals.
Neither one is better than the other, more advanced than the other, or really any better off in the long run, I'm convinced. They're just different. You can definitely tell what their parents do for entertainment. My cousin and his wife spend their time in the city, with people, doing things that require movement around the city. My wife and I spend our time either messing around in the woods, or sitting on the back porch listening to NPR or talking with friends. In rural areas, story telling is key to entertainment, so that's what we do.
And the imprint these two different lives are having on children who are relatively similar in genetics, socioeconomic status and amount of care in the home is simply fascinating.